Invasive lobular carcinoma (ILC)

Invasive lobular carcinoma starts within the milk glands (lobules) of your breast, and later invades surrounding breast tissue and possibly other parts of your body.

Unlike some other typer of breast cancer, ILC grows in a scattered pattern and may not present as a distinct lump. This creates challenges in detection with imaging tests like mammograms or self-exams.

ILC affects women more than men. Men can also get ILC, but it is very rare.

Risk factors for invasive lobular carcinoma

Risk factors for invasive lobular carcinoma include:

• Age: Women over 55 are at a higher risk of developing invasive lobular breast cancer.
• Certain noncancerous breast conditions: Conditions like lobular carcinoma in situ (LCIS) or atypical hyperplasia may elevate the risk of developing invasive breast cancer, including ILC.
• Dense breast tissue: Dense breast tissue can obscure cancers on mammograms and is associated with a higher risk of breast cancer.
• Genetics: A family history of breast cancer, particularly in close relatives like mothers, sisters or daughters, can elevate the risk.
• Long-term use of hormone replacement therapy (HRT): Prolonged use of hormone replacement therapy is linked to an increased risk of breast cancer, including ILC.
• Personal history of breast cancer: Having had breast cancer in one breast increases the likelihood of developing it in the other breast or experiencing a new cancer in the same breast.
• Reproductive factors: Factors such as early menstruation (before age 12), late menopause (after age 55), delayed childbirth or never having children may increase your risk of developing ILC.

Having one or more of these risk factors doesn't mean you’ll develop ILC. Many people diagnosed with breast cancer have no identifiable risk factors.

Invasive lobular carcinoma symptoms

If you have invasive lobular carcinoma, you may not experience any noticeable signs or symptoms. However, some signs of an issue may be visible that should be checked by your doctor.

ILC symptoms may include:

• Breast pain or discomfort
• Changes in breast shape or size
• Changes in the skin of the breast
• Nipple discharge
• Swelling of the breast or arm
• Thickening or hardening of breast tissue

If you notice any abnormal changes in your breast health, schedule an appointment with your doctor for further evaluation.

What is the most invasive type of breast cancer?

Inflammatory breast cancer (IBC) is considered the most invasive type of breast cancer. Unlike other types of breast cancer, IBC typically lacks a distinct lump or mass. Instead, IBC has notable signs such as redness, swelling, thick skin or a warm feeling. Additionally, you may notice that your breast is larger, firmer or bruised.

The term "inflammatory" is used because the breast frequently exhibits signs of inflammation due to cancer cells invading the skin and lymph nodes. This cancer type tends to progress and spread rapidly, earning its reputation as one of the most aggressive forms of breast cancer.

What is an invasive lobular carcinoma grade?

The invasive lobular carcinoma grade is a classification system used to judge the characteristics of cancer cells when examined under a microscope. This system helps doctors predict the speed at which your cancer cells may grow and spread to nearby tissue or other parts of your body.

Understanding the grading system

Invasive lobular carcinoma is graded on a scale ranging from one to three:

• Grade 1 (low grade): Cancer cells closely resemble normal breast tissue cells. They exhibit slow growth and spread, rendering this grade less aggressive.
• Grade 2 (intermediate grade): Cancer cells show some abnormal characteristics but are not visibly different from normal cells. They may grow and invade other areas of the body at a moderate pace.
• Grade 3 (high grade): Cancer cells appear significantly different from normal cells. They demonstrate aggressive behavior, including rapid growth and spread, often leading to a poorer prognosis.

Diagnosing invasive lobular carcinoma

A combination of exams and tests are used to diagnose invasive lobular carcinoma.

Typically, your doctor will start with a physical exam of your breasts and surrounding lymph nodes to look for lumps, thickening or changes in appearance.

Imaging tests play a crucial role in detecting and evaluating breast abnormalities. While mammograms are usually the initial screening tool for breast cancer, they may pose challenges in detecting ILC due to its widespread growth pattern, unlike other forms of breast cancer, including invasive ductal carcinoma.

Additional digital imaging tests, such as breast ultrasound or MRI, may be used to further evaluate any suspicious areas found during a physical exam or mammogram.

Biopsies for diagnosing invasive lobular carcinoma

If imaging studies reveal any abnormalities in the breast, a biopsy is performed to confirm the diagnosis. During a biopsy, a small sample of tissue is removed from the breast lesion using a thin needle or during a surgical procedure.

The tissue sample is examined under a microscope by a pathologist to determine whether cancer cells are present and to characterize the type of cancer, its hormone receptor status and grade. If cells are hormone receptor positive it means they have proteins that attach to estrogen and progesterone, which allows them to grow.

After a diagnosis of ILC is confirmed, further tests, such as more imaging studies and additional biopsies, may be performed to determine the extent of the cancer and whether it has spread to other parts of the body.

Invasive lobular treatments

Treatment for invasive lobular carcinoma may involve a combination of surgery, radiation therapy, chemotherapy, hormone therapy and targeted therapy.

Possible ILC treatments include:

• Surgery: Surgical options for ILC include a mastectomy, which involves the partial or full removal of the breast tissue, or a lumpectomy (breast conserving surgery). If you have a lumpectomy, your doctor will give you radiation therapy to kill any remaining cancer cells in your breast and reduce the risk of it returning. In some cases, a mastectomy might be followed by breast reconstruction surgery.
• Hormone therapy: Hormone therapy works by blocking estrogen or reducing estrogen levels in the body. It is often used for ILC that is hormone receptor positive.
• Chemotherapy: Chemotherapy may be used to shrink the tumor, reduce the risk of recurrence or treat cancer that has spread to other parts of the body.
• Targeted therapy: Targeted therapy drugs target certain pathways involved in cancer growth and progression.

Your care team at Aurora Health Care will use a collaborative approach to provide the best treatment possible. Supportive care services such as counseling, nutrition therapy, palliative care and physical therapy may also be offered to help you manage the physical and emotional challenges of cancer treatment.

What is the hardest form of breast cancer to treat?

Cancers that exhibit increased aggressiveness, resistance to treatment or an increased likelihood of recurrence are more challenging to treat.

Among these, triple-negative breast cancer (TNBC) is often considered the most difficult form of breast cancer to manage because of the absence of hormone receptors. This causes it to not respond to hormone-targeted therapies.

Similarly, inflammatory breast cancer has considerable treatment hurdles. It's aggressive and spreads rapidly and is often not detected until it’s in the advanced stages, making it less responsive to treatments.